QuestionQUESTION: I have a 2001 SLS that the battery went dead. I got a jump and charged battery and had the charging system and battery check three different times and each time everything was within spec's. However, the battery light on the dash is on and the information system on the dash says battery not charging/check charging system. However the information system also shows between 14.2 to 14.7 volts while driving depending what is on. If I still have a drain in the battery somewhere with the key off would this cause the battery light and message, or is there a switch or relay somewhere to did not set, or could it be the body control module. I did disconnect the Neg and Pos cables from the battery for about 20 to see if the computer need to reset. Does need to be disconnected longer? I also checked for codes with a OBII scanner and no codes. Suggestions?
ANSWER: Disconnecting the battery does absolutely NOTHING for the computer.
The battery light could be ON due to a fault in the alternator as it is putting out the correct voltage but is NOT putting out the correct amperage.
If the battery light is remaining ON with the ignition key OFF, Replace the instrument cluster as it has an internal short to ground.
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QUESTION: Do you know what fuse powers the three wire plug that goes into the alternator. Should there not be 12 volts going into one of the wires on the plug. Thanks
AnswerThe LARGE RED wire mared as BATT has battery voltage at all times.
Terminal "D" orange wire has battery voltage at ALL times.
Terminal "C" gray wire is your FIELD wire going back to the computer.
Terminal "B" red wire is your 5 volt reference wire back to the computer.
Terminal "A" is NOT utilized.
You will ONLY have battery voltage on the BIG RED wire by itself and Terminal "D" the orange wire.
